JP2000305288A - Image forming method using ferroelectric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method in which electrification, imagewise exposure and development can be carried out in a light room, an image is formed as a color image and the electrification, imagewise exposure and image can be written and erased at any time, plural toner images can be formed when an image is written once, high mechanical strength is ensured, surface scuffing due to toner development or the like is suppressed, any toner developing system may be adopted and printing on many sheets is suitably carried out. SOLUTION: A ferroelectric element with a ferroelectric layer comprising an inorganic oxide ferroelectric and a photoset resin on an electrically conductive substrate is prepared and the electric dipoles of the ferroelectric in the ferroelectric layer are aligned in one direction. The electric dipoles of a part corresponding to an image area or a non-image area are inverted. The ferroelectric layer are uniformly heated to the Curie point or below and cooled to form an electrostatic latent image. This electrostatic latent image is developed with a toner. The photoresist resin preferably has hydroxyl groups and the hydroxyl equivalent of the photoset resin is preferably 50-400.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method, and more particularly, to an image forming method of forming an electrostatic latent image using a ferroelectric substance and then visualizing the electrostatic latent image using toner. About the method.

[0002]

2. Description of the Related Art In general, an electrophotographic method, which is one of image forming methods used in copying machines and printers, charges a photosensitive member having a photosensitive layer composed of a photoconductor and then exposes the photosensitive member by image exposure. Form an electrostatic latent image on the photosensitive layer of the body, develop it with electrostatic toner, transfer the toner image on the photoconductor to film, plain paper, etc., and fix the transferred toner image To form a visible image. To form the same visible image again, the toner adhered to the photoconductor is cleaned, charged again, and the same steps such as image exposure, transfer, and fixing are repeated. Therefore, when a plurality of identical images are created, the copying speed is limited, and high-speed copying is difficult.

In order to solve this problem, "Photographic Science and Engineering (Ph.
otographic Science and Engineering ”Vol. 25 (1981)
Years) pp. 35-39 and 209-215 propose an electrophotographic photosensitive member having memory properties. According to this method, once image exposure is performed, a plurality of copies can be made by repeating the above-described steps from development to fixing.

However, the electrophotographic photoreceptor described in this document cannot store a latent image formed by image exposure for a long period of time, has a problem in memory, and cannot store it in a bright room. In addition, printing durability and environmental stability are poor, and they have not been put to practical use.

Also, a ferromagnetic material is used to form a latent image having memory properties according to the magnitude of its magnetic susceptibility, developed using a magnetic toner, transferred, fixed and transferred to a plurality of visible images by one image writing. Such as "Repro MG8000" (manufactured by Iwasaki Tsushinki), "Varipress M450" (Bull-Nipson)
Has been put to practical use.

Further, Japanese Patent Application Laid-Open No. Hei 5-221139 discloses that after an organic ferroelectric layer is subjected to a poling (dipole orientation) treatment, light is applied to write an image so that the exposed portion has a Curie point (Tc) or more. There has been proposed a recording method in which a latent image is formed by heating the latent image, the continuous copying is possible, and the latent image can be stored.

[0007]

As described above, the conventional electrophotographic method using a photoconductor is used in various fields such as a printer, a copying machine, and a direct plate making. Must be performed in a dark room,
Also, in order to create a plurality of identical images, the toner attached to the photoconductor is cleaned and then charged again, and then the same processes such as image exposure, transfer, and fixing are repeated. High-speed copying is difficult.

Further, in the method using a ferromagnetic material, a magnetic head is used as a writing head, so that the resolution is limited, and it is difficult to produce a color magnetic toner, so that a color image cannot be produced. There is a point.

Further, in writing an image using an organic ferroelectric substance, light is irradiated and the exposed portion is cured at the Curie point (T
c) In the method of forming a latent image by heating as described above, since the surface of the organic ferroelectric material has low mechanical strength, the surface is easily scratched by toner development or the like, and such a scratch causes the non-image area to be damaged. And the contamination of the non-image area increases as the number of printed sheets increases. For this reason, there are problems that the method of toner development is limited and that the method is not suitable for printing many sheets.

There is also an image forming method using a ferroelectric element manufactured by dispersing an inorganic ferroelectric powder in a resin.

[0011] The binder resin has a hydrophilic group such as a hydroxyl group or a carboxyl group. On the other hand, since the inorganic oxide is hydrophilic, the volume content of the powder in the mixture of the binder resin and the inorganic oxide powder can be increased by using a binder having a high hydrophilicity.

When a ferroelectric element is manufactured, the use of a hydrophilic binder resin makes it possible to increase the volume fraction of the ferroelectric substance in the ferroelectric element. It is very useful for obtaining an electrostatic latent image with high contrast.

The problem to be solved by the present invention is that charging, image exposure and development can be performed in a bright room without requiring large equipment for manufacturing, and colorization of an image is possible. Charging, image exposure, writing and erasing of images are possible at any time, multiple images of the same toner can be created by one image writing, and the mechanical strength is high. An object of the present invention is to provide an image forming method using a ferroelectric material, which is hardly damaged, does not limit the method of toner development, and is suitable for printing many sheets.

[0014]

Means for Solving the Problems As a result of intensive studies, the present inventors have developed a method of forming a latent image using an inorganic oxide ferroelectric and forming a toner image by electrophotography. And completed the present invention.

That is, the present invention provides (1) a ferroelectric element in a ferroelectric element having a ferroelectric layer comprising an inorganic oxide ferroelectric and a resin on a conductive support. A first step of arranging the ferroelectric dipoles in the body layer in one direction, (2) a second step of inverting dipoles in a portion corresponding to an image portion or a non-image portion, and (3) a ferroelectric layer A third step of uniformly heating to below the Curie point and then cooling to develop an electrostatic latent image, and (4) a fourth step of developing the electrostatic latent image with toner In the above, there is provided an image forming method in which the resin used for the ferroelectric layer is a photocured resin.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A ferroelectric element used in an image forming method of the present invention comprises a ferroelectric layer and a conductive support layer. As shown in FIG. The support layer may be in a close contact state, or an intermediate layer may be provided between the ferroelectric layer and the support layer. Further, a film for protecting the ferroelectric may be provided on the upper layer of the ferroelectric layer.

The inorganic oxide ferroelectric used in the ferroelectric layer may be capable of reversing the dipole orientation and the dipole in the image portion or the non-image portion by corona charging or the like. , Which decrease when the temperature is raised from room temperature.
Further, as these inorganic oxide ferroelectrics, perovskite-type crystals such as barium titanate and PZT (lead zirconate titanate) are well known. In the present invention, those having a layered structure are preferable. Bismuth layered compounds are particularly preferred. These inorganic oxide ferroelectrics can be used alone or in combination of two or more. As such an inorganic oxide ferroelectric, for example, the general formula (1)

[(Bi ₂ O ₂ ) ²⁺ (XY ₂ O ₇ ) ^2- ]

Wherein X is Sr, Pb or Na _0.5 B
i represents _0.5 , and Y represents Ta or Nb. An inorganic ferroelectric oxide represented by the general formula (2):

[0020] _{[X n Bi 4 Ti n +} 3 O 3n + 12]

Wherein X is Sr, Ba, Pb or Na
_0.5 represents Bi _0.5 , and n represents 1 or 2. And the like. More specifically, SrBi ₂ Ta ₂ O ₉ , SrBi ₂ Nb
₂ O ₉ , SrBi ₄ Ti ₄ O ₁₅ , and the like.

The photo-cured resin used for the ferroelectric layer can be used without any particular limitation as long as it is a cured resin comprising an ultraviolet-curable composition containing an ultraviolet-curable compound used for electronic materials and coatings. it can. Further, in addition to the ultraviolet curable composition, an electron beam curable composition or a radiation curable composition can also be used.

The ultraviolet-curable compound is a monomer, dimer, trimer, tetramer or multimer having at least one actinic ray-curable functional group, and can be appropriately selected depending on the required physical properties. it can. Bifunctional with good curing performance (2 per molecule)
Resins having at least two curable functional groups) are preferred. A composition containing these compounds may contain a polymerization initiator.

As the actinic ray-curable functional group, for example,
Examples include an acryl group, a methacryl group, a vinyl group, a vinyloxy group, a chloroacryl group, an acrylamide group, a methacrylamide group, an epoxy group, and a mercapto group. Among these functional groups, an acryl group, a methacryl group, and an epoxy group are preferable, and an acryl group is particularly preferable.

The resin used for the ferroelectric layer preferably has a hydrophilic functional group such as a hydroxyl group, a carboxyl group, or an amino group in the side chain, and more preferably has a hydroxyl group or a carboxyl group in the side chain. Those having a hydroxyl group are particularly preferred.

The hydroxyl equivalent of the resin used for the ferroelectric layer is as follows:
The range is preferably from 50 to 1,000, more preferably from 50 to 400, further preferably from 100 to 300, and particularly preferably from 150 to 270.

As the polymerization initiator, thioxanthones,
Examples include acetophenone-based and benzophenone-based.

A composition containing a compound having an actinic ray-curable functional group may be used in combination with a photopolymerization accelerator. Examples of the photopolymerization accelerator include p-dimethylaminobenzoic acid ester.

A composition containing a compound having an actinic ray-curable functional group may be used in combination with a polymerization inhibitor in order to increase storage stability.

A composition containing a compound having an actinic ray-curable functional group may be used in combination with a leveling agent in order to improve the surface smoothness of the ferroelectric layer. It is not suitable because it lowers the electric resistance of the ferroelectric layer, and a fluorine-based leveling agent is preferred.

Examples of the fluorine-based leveling agent include the “Megafac” series manufactured by Dainippon Ink and Chemicals, Inc.

A dispersant may be used in combination with the composition containing the compound having an actinic ray-curable functional group in order to improve the moldability of the ferroelectric layer. An ionic dispersant is not suitable because it lowers the electric resistance of the ferroelectric layer, and is preferably a silane coupling agent.

Examples of the silane coupling agent include KBM series, KBE series, KA series, and KBC series manufactured by Shin-Etsu Silicone Co., Ltd.

When a binder resin having a low volume resistance at room temperature is used for the ferroelectric layer, a first step of arranging the ferroelectric dipoles in one direction and a dipole of a portion corresponding to an image portion or a non-image portion are performed. In the second step of inverting the dipole, when the dipole is oriented using, for example, corona charging, the corona is not sufficiently charged, and the dipole orientation is hardly caused to occur. Gets worse. Also, in the inversion of the dipole in the second step, the same thing occurs, and the degree of orientation of the dipole to be inverted deteriorates, which is not preferable.

If the orientation of the dipoles in the ferroelectric layer is not sufficient, the surface potential generated by the change in the electric resistance of the ferroelectric layer and the pyroelectricity of the ferroelectric material is reduced, and the contrast of the surface potential is reduced. Becomes insufficient. If the contrast of the surface potential is not sufficient, the toner tends to adhere to the non-image area when forming the toner image, and the toner hardly adheres to the image area, and the quality of the toner image deteriorates. Would.

The conductive support layer is not particularly limited as long as it has necessary mechanical strength and smoothness and has conductivity, and the material is not particularly limited. In terms of stability, etc., metals such as platinum, aluminum, copper and nickel, conductive polymers and carbon black,
Conductive inorganic substances such as indium tin oxide (ITO),
And the like, and a laminate obtained by laminating a conductive film on plastic, paper, or another insulating substrate may be used.

The ferroelectric element used in the image forming method of the present invention includes, for example, (A) a method of forming a ferroelectric layer on a conductive support layer, and (B) a ferroelectric layer and a conductive support. It can be manufactured by a method in which the body layers are separately manufactured and then bonded.

As the method (A), a mixture of a ferroelectric powder material and a composition containing a compound having an actinic ray-curable functional group is prepared by dipping, bar coating, roll coating, spraying, or the like. A ferroelectric layer can be manufactured by applying the composition on a substrate by a coating method, a spin coating method, a doctor blade method, or the like, and then irradiating and curing the applied ultraviolet light.

As the method (B), a mixture of a ferroelectric powder material and a composition containing a compound having an actinic ray-curable functional group is prepared by dipping, bar coating, roll coating, spraying, or the like. After applying by a coating method, a spin coating method, a doctor blade method, and the like, and then curing by irradiating ultraviolet rays, a film is formed, and a ferroelectric film is formed, and then a support is formed using a conductive adhesive. A method in which the layer is brought into close contact with a layer, and the like.

A solvent may be used in a mixture of the ferroelectric powder material and a composition containing a compound having an actinic ray-curable functional group. When a solvent is used, a solvent that does not alter the inorganic oxide ferroelectric substance and that can dissolve or disperse the resin material can be used. Examples of such a solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; alcohol solvents such as methanol, ethanol, isopropanol and butanol; cellosolve solvents such as ethyl cellosolve, methyl cellosolve and butyl cellosolve; Amide solvents such as dimethylformamide and methylpyrrolidone; chlorine solvents such as dichloromethane, 1,2-dichloroethane and 1,1,2-trichloroethylene; and aromatic nonpolar solvents such as toluene, xylene and mesitylene. . These solvents may be used as a mixture of two or more kinds in an appropriate ratio.

In particular, at present, which is extremely sensitive to environmental problems, it is very preferable to use an aqueous solvent. Therefore, it is preferable to use a mixed solvent system which can contain water. However, it is preferable not to use an aqueous solvent as much as possible.

The thickness of the ferroelectric layer is determined by using a method of orienting the dipole by applying an electric field. If the thickness is too large, a high charging voltage is required or charging tends to be required repeatedly. So it ’s not desirable,
On the other hand, if it is too thin, the difference between the surface potential of the image area and the surface potential of the non-image area becomes small, and the contrast of the visible image with the toner tends to decrease.
m is preferable, a range of 10 μm to 200 μm is more preferable, and a range of 15 μm to 100 μm is particularly preferable.

When a ferroelectric element is formed, the element may be formed by one film forming operation, but the required film thickness may be obtained by dividing into several steps. That is, about 5 μm by one film forming operation.
A film having a thickness of about 50 μm may be formed by forming a film having a thickness of m and repeating this operation ten times.

In the first step of the image forming method of the present invention, the method of arranging the ferroelectric dipoles in the ferroelectric layer in one direction (hereinafter referred to as dipole alignment treatment) is based on corona charging. A charging method used in electrophotography such as a method and a method using a roller electrode can be used.

The dipole alignment treatment by corona charging can be performed using a corona charger of a usual corotron type or scorotron type. Further, the dipole orientation treatment by roller charging is performed by bringing a conductive rubber roller to which a high voltage is applied into contact with a dielectric layer, for example, having a resistance value of 10 5 to 1.
A method in which a voltage of several hundred volts or more is applied to a conductive rubber roller having a resistance of about 09 Ωcm to charge, a resistance value of 10 3 to 10 5 Ω
There is a method of attaching a fibrous wire rod having a thickness of cm to the surface of the conductive roller in a brush shape to enhance the contact property, and applying a high voltage to the conductive roller to charge the conductive roller. In both cases, a suitable method may be selected according to the system configuration of the apparatus.

The time required for dipole alignment is corona voltage,
It depends on the applied voltage of the roller electrode or its shape, and can be appropriately set according to the system configuration of the apparatus, the method of use of the apparatus, or the application.

In the second step of the image forming method of the present invention, as a method of inverting the dipole of the portion corresponding to the image portion or the non-image portion, a corona charge is applied to the portion corresponding to the image portion or the non-image portion through a mask. A method of inverting a dipole, a method of inverting a dipole corresponding to an image portion or a non-image portion using a stylus head, a method of inverting a dipole of an image portion or a non-image portion by ion flow, and the like. Is mentioned.

When the volume resistivity of the ferroelectric substance is small, for example, 10 10 Ωcm, the electric field of the corona is not sufficiently applied, and the orientation of the dipole and the reversal of the dipole in the image portion or the non-image portion are caused by Since the writing is not performed sufficiently, there is a tendency that image writing cannot be performed satisfactorily. Therefore, it is preferable that the volume electric resistivity of the ferroelectric material is large.

When the relative permittivity of the ferroelectric substance is large, for example, 1000 or more, the electrostatic capacity is large, so that at a film thickness of about 100 μm, a sufficient electrostatic contrast for toner development can be obtained. Because they tend not to be
The relative permittivity of the ferroelectric material is preferably small.

The capacitance of the ferroelectric layer can be reduced by increasing the film thickness. However, an increase in the corona voltage required for dipole orientation or the like, or an increase in the energy required during heating / cooling are required. It is not preferable to increase the film thickness, since it tends to increase remarkably.

In order to generate a surface potential difference between the written latent image portion and the non-image portion, the third method of forming an image of the present invention is performed.
In the process, the ferroelectric layer in which the dipole of the portion corresponding to the image portion or the non-image portion is inverted is heated below the ferroelectric-paraelectric phase transition point (Curie point) of the dielectric, and then cooled. To develop an electrostatic latent image. It is indispensable that the ferroelectric material has ferroelectricity at room temperature, and since the orientation of the dipole of the ferroelectric material is found to be beyond the Curie point, from the viewpoint of stability of image information, the heating temperature is It is necessary to keep it below the Curie point.

By heating the ferroelectric layer to a temperature below the Curie point, the spontaneous polarization of the ferroelectric decreases, the bound surface charges become free charges, and in the heated state, the ferroelectric layer This free charge leaks because the electrical resistance is low.

By cooling from the heating state, the spontaneous polarization reversibly returns to its original size, but the leaked surface charge is irreversible, so that a potential is generated due to the spontaneous polarization. Therefore, the electric resistance of the ferroelectric layer needs to be reduced by increasing the temperature from room temperature.

It is suitable that the temperature of the ferroelectric layer is reduced immediately after the heating. In the case of a device in which a heating element such as a heat roll contacts the ferroelectric substance to heat the ferroelectric layer, the heating element is heated. The smaller the heat capacity, the better.

As a means for heating the ferroelectric, a method of irradiating light or the like and converting the energy into heat can be used. The method of irradiating light is particularly preferable in that the method is non-contact and the temperature is lowered immediately after heating.

The light source of the light irradiation device includes, for example, an infrared lamp, a halogen lamp, a xenon lamp, a metal halide lamp, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a laser and the like.

In the method of heating by irradiating light, the light irradiation time and irradiation intensity require a certain intensity or more, but the emission wavelength of the light source, the absorption wavelength of the light absorbing material,
Since the optimum value of the light intensity to be irradiated varies depending on conditions such as the heat capacity of the ferroelectric element, it is necessary to select appropriate conditions as appropriate. That is, an appropriate value may be selected for the intensity of the irradiated light depending on conditions such as the emission wavelength, the absorption wavelength of the light absorbing substance, and the heat capacity of the ferroelectric element.

Irradiation uniformly over time and in a plane is effective in uniformly heating the ferroelectric layer.

In the fourth step of the image forming method of the present invention,
After forming an electrostatic latent image, at a temperature showing ferroelectricity,
The latent image is developed into a visible image by developing using an electrostatic powder toner or a liquid toner.

As the electrostatic powder toner and the liquid toner, appropriate ones may be selected from commercial products.

The toner image developed on the surface of the ferroelectric layer is transferred to the plain paper or film electrostatically by charging the plain paper or the back of the film after laminating the plain paper or film. After that, fixing may be performed.

In order to continuously produce a plurality of identical images, if the surface of the ferroelectric layer has a surface potential contrast that allows electrostatic toner development, the electrostatic toner development, transfer, and fixing are successively performed. Just do it.

When the surface potential contrast or the like is lowered due to the influence of the transfer conditions or the surrounding environment, the surface potential contrast is formed by heating and cooling the ferroelectric layer, if necessary, and then the toner development is performed. Then, transfer and fixing may be performed.

[0064]

The present invention will be described in more detail with reference to the following examples. However, the invention is not limited to these examples.

Example 1 Strontium carbonate (SrC)
O ₃₎ 12.00 g, titanium oxide (TiO ₂₎ 25.97
g of bismuth trioxide (Bi ₂ O ₃ ) and 75.75 g of bismuth trioxide, the mixture was mixed in an electric furnace at 1000 ° C. for 3 hours.
Time kept. The mixture after sintering is crushed using a mortar,
Powder SrBi ₄ Ti ₄ O ₁₅ was obtained.

20 g of the thus obtained SrBi ₄ Ti ₄ O ₁₅ powder, 98 parts of “epoxy ester 70PA” (epoxy acrylate manufactured by Kyoeisha Chemical) and “benzyl dimethyl ketal” (photopolymerization initiator of Toa Gosei Co., Ltd.) 5) g of the two-part composition was dispersed and mixed using a planetary-type fine-particle grinder "PULVERISETTE 7" (manufactured by FRITSCH).

The dispersion mixture obtained in this manner was applied to an alumite-treated aluminum substrate using a bar coater so that the film thickness after drying was about 5 μm. Irradiate (40 mW, 60 seconds)
A ferroelectric layer was formed. This operation was repeated seven more times to obtain a ferroelectric element having a thickness of about 50 μm.

The pulse width of the ferroelectric element is 0.2
The alignment treatment was performed by applying a negative corona pulse having a voltage of 6 kV for 100 times per second.

Through an arbitrary mask, a pulse width of 0.2
By applying a positive corona pulse having a voltage of 6 kV for 100 times per second, the polarization was inverted only in the portion corresponding to the image portion.

Next, the ferroelectric element was heated to 150 ° C. using a heater, and then cooled to form an electrostatic latent image. When the electrostatic latent image was visualized on the ferroelectric element treated in this manner using a powder toner having a positive polarity, the toner adhered to the portion where the polarization was inverted. This toner image was transferred to plain paper and fixed to obtain a first arbitrary image.

Further, the ferroelectric element after the visible image has been transferred to the plain paper is heated and cooled, and the development, transfer and fixing are repeated in the same manner as in the first sheet, whereby a plurality of arbitrary sheets can be obtained. Image was obtained.

After storing this ferroelectric element in a bright room for one month, the ferroelectric element was heated to 150 ° C. using a heater and then cooled to form an electrostatic latent image. When the electrostatic latent image was visualized on the thus treated ferroelectric element using the powder toner of the positive electrode, the toner adhered only to the portion where the polarization was inverted. This toner image was transferred to plain paper and fixed to obtain a similar image.

After the visible image is transferred to plain paper, the ferroelectric element is heated, then cooled, and development, transfer, and fixing are repeated in the same manner as in the first sheet, whereby a plurality of arbitrary images are transferred. I got

Further, the ferroelectric element was subjected to an alignment treatment by applying a negative corona pulse having a pulse width of 0.2 seconds and a voltage of 6 kV 100 times. By applying a positive corona pulse having a pulse width of 0.2 seconds and a voltage of 6 kV 100 times through an arbitrary mask, the polarization was inverted only in the portion corresponding to the image area. Next, the ferroelectric element was heated to 150 ° C. using a heater and then cooled to form an electrostatic latent image. When the electrostatic latent image was visualized on the ferroelectric element treated in this manner using a powder toner of positive polarity, the toner adhered only to the portion where the polarization was inverted. This toner image is transferred to plain paper and fixed,
The second arbitrary image was obtained.

Further, the ferroelectric element after the transfer of the visible image to plain paper is heated and cooled, and the development, transfer and fixing are repeated in the same manner as in the first sheet, whereby a plurality of arbitrary sheets can be formed. Image was obtained.

Example 2 SrBi ₄ T obtained in Example 1
20 g of i ₄ O ₁₅ powder and “Epoxyester 3002”
M "(epoxy acrylate manufactured by Kyoeisha Chemical Co., Ltd.) 75
10 g of a composition consisting of 23 parts of “Epoxyester 40EM” (epoxy acrylate manufactured by Kyoeisha Chemical Co., Ltd.) and 2 parts of “benzyldimethyl ketal” (photopolymerization initiator manufactured by Nippon Kayaku Co., Ltd.) The mixture was dispersed and mixed using a crusher “PULVERISETTE 7” (manufactured by FRITSCH).

The dispersion mixture thus obtained was applied on an alumite-treated aluminum substrate using a bar coater so that the film thickness after drying was about 25 μm. Irradiation (300 mW, 60 seconds) was performed to form a ferroelectric layer, thereby obtaining a ferroelectric element.

This ferroelectric element has a pulse width of 0.2
The alignment treatment was performed by applying a negative corona pulse having a voltage of 6 kV for 100 times per second.

Through an arbitrary mask, a pulse width of 0.2
By applying a positive corona pulse having a voltage of 6 kV for 100 times per second, the polarization was inverted only in the portion corresponding to the image portion.

Next, the ferroelectric element was heated to 150 ° C. using a heater, and then cooled to form an electrostatic latent image. When the electrostatic latent image was visualized on the ferroelectric element treated in this manner using a powder toner having a positive polarity, the toner adhered to the portion where the polarization was inverted. This toner image was transferred to plain paper and fixed to obtain a first arbitrary image.

Further, the ferroelectric element after the visible image has been transferred to plain paper is heated and cooled, and development, transfer and fixing are repeatedly performed in the same manner as in the first sheet, whereby a plurality of arbitrary sheets can be obtained. Image was obtained.

After storing this ferroelectric element in a bright room for one month, the ferroelectric element was heated to 150 ° C. using a heater and then cooled to form an electrostatic latent image. When the electrostatic latent image was visualized on the thus treated ferroelectric element using the powder toner of the positive electrode, the toner adhered only to the portion where the polarization was inverted. This toner image was transferred to plain paper and fixed to obtain a similar image.

After the visible image is transferred to plain paper, the ferroelectric element is heated, cooled, and repeatedly subjected to development, transfer, and fixing in the same manner as in the first sheet, thereby forming a plurality of arbitrary images. I got

Further, the ferroelectric element was subjected to an alignment treatment by applying a negative corona pulse having a pulse width of 0.2 seconds and a voltage of 6 kV 100 times. By applying a positive corona pulse having a pulse width of 0.2 seconds and a voltage of 6 kV 100 times through an arbitrary mask, the polarization was inverted only in the portion corresponding to the image area. Next, the ferroelectric element was heated to 150 ° C. using a heater and then cooled to form an electrostatic latent image. When the electrostatic latent image was visualized on the ferroelectric element treated in this manner using a powder toner of positive polarity, the toner adhered only to the portion where the polarization was inverted. This toner image is transferred to plain paper and fixed,
The second arbitrary image was obtained.

Further, the ferroelectric element after the visible image has been transferred to plain paper is heated and cooled, and development, transfer and fixing are repeatedly performed in the same manner as in the first sheet, whereby a plurality of arbitrary sheets can be formed. Image was obtained.

Comparative Example SrBi ₄ Ti ₄ obtained in Example 1
5 g of a resin solution obtained by mixing 5 g of O ₁₅ powder, 10 parts of “BM-S” (polyvinyl butyral having a hydroxyl equivalent of about 220, manufactured by Sekisui Chemical Co., Ltd.), 70 parts of xylene, and 20 parts of butyl cellosolve, The mixture was dispersed and mixed using a crusher “PULVERISETTE 7” (manufactured by FRITSCH).

The thus obtained dispersion mixture was applied on a nickel substrate using a bar coater so that the film thickness after drying was about 100 μm.
The solvent was removed by heating at 900 ° C for 5 minutes in an electric furnace.
Sintered for hours.

As a result, the nickel substrate was oxidized and the ferroelectric was not sintered, so that a ferroelectric element could not be obtained.

Even if a ferroelectric element is obtained by sintering as in the comparative example, the element cannot be manufactured because the conductive substrate is oxidized or the ferroelectric is not sintered. When an ultraviolet curable resin is used as the binder resin as in the first and second embodiments, a ferroelectric element can be manufactured at a low temperature in a short time.

[0090]

According to the image forming method using the ferroelectric element of the present invention, the latent image can be stably stored in a bright room for a long period, and the image can be written and erased as needed. Further, according to the image forming method using the ferroelectric element of the present invention, since the contrast of the surface potential at the time of toner development is high, a plurality of toner images can be formed with high quality by writing a latent image once. It is possible.

[Brief description of the drawings]

FIG. 1 is a sectional view of a ferroelectric element of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ferroelectric layer 2 Ferroelectric 3 Resin 4 Support layer

Claims (7)

[Claims] (1) In a ferroelectric element having a ferroelectric layer made of an inorganic oxide ferroelectric and a resin on a conductive support, a ferroelectric dipole in the ferroelectric layer is removed. A first step of arranging in one direction, (2) a second step of inverting a dipole in a portion corresponding to an image portion or a non-image portion, and (3) after uniformly heating the ferroelectric layer below the Curie point. A third step of cooling to develop an electrostatic latent image and (4) a fourth step of developing the electrostatic latent image using toner, wherein the resin used for the ferroelectric layer is light. An image forming method characterized by being a cured resin. 2. The image forming method according to claim 1, wherein the ferroelectric layer has a structure in which an inorganic oxide ferroelectric is dispersed in a resin. 3. The image forming method according to claim 1, wherein the photocured resin comprises a composition containing a compound having an actinic ray-curable functional group. 4. The image forming method according to claim 1, wherein the photocured resin has a hydroxyl group, a carboxyl group or an amino group. 5. The image forming method according to claim 1, wherein the photocured resin has a hydroxyl group. 6. The image forming method according to claim 5, wherein the hydroxyl equivalent of the photocured resin having a hydroxyl group is in the range of 50 to 400. 7. A method in which a ferroelectric layer is applied with a dispersion comprising an inorganic oxide ferroelectric and a composition containing a compound having an actinic ray-curable functional group, and is then irradiated with actinic light. The image forming method according to any one of claims 1 to 6, wherein the film is obtained by the following method.